As a circularly polarized wave antenna for a microwave band used in satellite broadcasts, satellite communications and the like, a micro strip antenna (MSA) is prevailing, which is a planar antenna that includes a radiating element on the surface of a dielectric substrate and a ground conductor on the back thereof.
In FIG. 1, there is shown one example of the MSA, Reference numeral 10 denotes a dielectric substrate, 12 an almost square radiating element, and 14 a ground conductor. Where such MSA is provided on a window glass of a vehicle, the dielectric substrate 10 is structured by the window glass of a vehicle, the radiating element is patterned on the outer surface of the window glass, and the ground conductor is patterned on the inner surface of the window glass. Feeder lines are connected to the radiating element and ground conductor, respectively, but the feeder line to the radiating element has to be provided passing through the window glass, which is hard for the vehicle window glass. Consequently, it is difficult to form the MSA on the window glass of a vehicle.